Question about a grease gun

[Silverstreak]

I hope its okay to ask this here. I got my own grease gun for my cart instead of using my husbands, which is always a mess and in the barn.
Its working, but I have a question about its anatomy. If the plunger is as long as the barrel, I don't understand what function it serves. Is there just not that much grease in a cartridge, because when I push the plunger all the way in, it must go all the way to the end of the barrel. I'm thinking that there just isn't much grease in a new cartridge. Is that right?
Also.......do I pull that plunger out a bit for storage?
Thanks!

[kab69440]

The plunger rod goes to the front of the gun. The spring loaded plunger itself moves forward as grease is emptied from the cartridge. Pull the plunger all the way out and lock it( some turn 90deg some just pull to the side) load a cartridge and replace the cap. Unlock the plunger rod and push it all the way back in. It might take a few pumps to get the air out of your new fitting, but eventually it will come out. When the cartridge gets near to empty, you can pull the plunger rod out a few times to help swab any leftover grease off the cartridge wall.

If you don't have one on the gun already, I highly recommend a 12" or longer rubber whip. The steel tube is useless except for machinery maintenance where the zerks are easily exposed. For carts and cars, a good long rubber whip is worth several times its weight in gold!

[Silverstreak]

Thanks kab.
I know how to load it. I'm just wanting an image or description on how that plunger works. There must be very little grease in the cartridge, if the plunger goes completely back into the barrel, right? I put a new cartridge in, and the plunger (which is a long rod) goes completely back into the barrel. I know it has a seal of some sort on the end, so grease doesn't come back out the rod. Just seems like there must never be much grease in those cartridges, right? I thought that rod would stick out and slowly move forward, as the grease is used up. But its all the way in from the start.
The You Tube videos I've watched show the same thing. I'm just wanting to understand why its all the way inside the barrel already, when its a new cartridge.
I hope I'm not confusing you!
Yes, I bought a flexible extension tube too.

[kab69440]

If you look at it next time it's empty, the rod travels through the center of the disc and seal. The disc and seal travel on the rod and are moved into the tube by a spring. As the grease empties from the tube, the disc and seal can move forward on the rod. The disc and seal are not always at the far end of the rod, as they appear to be just by glancing at it. When the tube is near full, the disc and seal are at the back of the grease tube and are moved a bit forward by the spring as the grease is moved out of the gun.

Do you have a caulking gun? If you watch that in action, you may get a little clearer insight on what is happening inside the grease tube. The difference being that the plunger is affixed to the end of the rod instead of traveling its length.

[chloe]

Maybe I can add on to the good info kab has given and simplify it just a bit. To answer your question, the tube you buy is about 3/4 to 4/5 full. When you release the plunger rod, the tube scraper stops at the grease pack while the rod it rides on continues to slide into the grease a bit. The spring applies pressure on the scraper, not the rod. If you push to rod you can push it all the way into the grease but the scraper and spring remain at the end of the grease pack, applying pressure for the next pump.

[AzPete]

The rod and the plunger that pushes the grease are not tied together....they slide...tubes I have had were almost full all the time.

[Silverstreak]

Okay! I get it now!
So to begin with, a fair part of the rod is actually below the spring and seal and goes through the grease?
Cool! Thanks a bunch!!

[AzPete]

You got it...........

[kab69440]

Many thanks... I wasn't sure how else to explain it!